Paleoclimatology is a fascinating discipline that combines paleontology with climate studies. Understanding what the Earth’s climate was like millions of years ago can prove very valuable in understanding today’s weather. In addition, it’s just plain cool to find out facts such as that dinosaurs once roamed Antarctica, tropical fruits used to grow in Oregon, and just 8,500 years ago the temperature in Greenland was about 10°F (5°C) warmer than it is today. Paleoclimatologists discover this information by examining animal and plant fossils, conducting ice core studies, and examining soils and rocks buried deep underground. Clues may be found in some of the most unlikely places. For instance, when ancient pine needles hoarded by rats 30,000 years ago were discovered, the composition of the plant matter was analyzed to learn what carbon dioxide levels were like back then.